Hey guys, Anyone know what sort of tubes are in a stock 2012 WR450F? I need to change the rear tyre for the first time (still has stock rear tyre) and was thinking about getting a heavy duty tube but the current tube has nothing wrong with it, never goes down, never had a flat. Is this because they already come out with heavy duty tubes? Also have any of you ever tried a Pirelli Heavy duty tube? I run Pirelli tyres and they're great so I assume their tubes are awesome as well, would like to know what you guys think though. Cheers, Nath.